1. Field of the Invention
The present invention relates to a method for manufacturing a numeric display; and particularly, to a manufacturing method for a housing of a numeric display.
2. Description of Related Art
A numeric display is a display module for displaying graphics and symbols using LEDs or electro-optical substances. The numeric display has been widely used in the indicators or display elements of many modern electronic products, such as family electric appliances, acoustic electric devices, and cameras.
In a traditional manufacturing process, a reflecting cover of the numeric display is first formed and a housing of the numeric display is then formed by dispensing epoxy into the reflecting cover. Next, the housing of the numeric display with epoxy is baked to cure. Then, a printed circuit board having LED chips is connected and reflowed on the housing.
However, the traditional method has the following disadvantages.
1. Long processing time: The traditional dispensing process has a baking step to cure the epoxy. For example, the epoxy is heated at 110° C. in time period of 1.5 hours (i.e., pre-curing) and then is cured at 120° C. in time period of 3 hours (i.e., post-curing). Therefore, the traditional manufacturing time of the numeric display is long and the cost cannot be reduced.
2. More defects in the product: There are problems of leakage of epoxy or un-uniform dispensing of epoxy in the traditional method, and the problems result in recesses on the lighting surface of the numeric display after the baking process. Consequently, the defects of bubbles, light spots or un-uniform light occurred in the numeric display.
3. Variant in the product structure: As discussed in points 1 and 2, a thermal stress is generated in the epoxy during the baking step so that the house would be deformed. Therefore, the product has deformations thereon and the manufacturing yield is low.
Consequently, with regard to the resolution of defects illustrated hereinbefore, the inventors of the present invention propose a reasonably and effectively designed solution for effectively eliminating such defects.